/*
 * Copyright 2007-2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License. 
 */
package org.aopalliance.intercept;

import java.lang.reflect.AccessibleObject;

/**
 * This interface represents a generic runtime joinpoint (in the AOP
 * terminology).
 * <p>
 * A runtime joinpoint is an <i>event</i> that occurs on a static joinpoint
 * (i.e. a location in a the program). For instance, an invocation is the
 * runtime joinpoint on a method (static joinpoint). The static part of a given
 * joinpoint can be generically retrieved using the {@link #getStaticPart()}
 * method.
 * <p>
 * In the context of an interception framework, a runtime joinpoint is then the
 * reification of an access to an accessible object (a method, a constructor, a
 * field), i.e. the static part of the joinpoint. It is passed to the
 * interceptors that are installed on the static joinpoint.
 * 
 * @see Interceptor
 */
public interface Joinpoint {
	/**
	 * Proceeds to the next interceptor in the chain.
	 * <p>
	 * The implementation and the semantics of this method depends on the actual
	 * joinpoint type (see the children interfaces).
	 * 
	 * @return see the children interfaces' proceed definition.
	 * @throws Throwable
	 *             if the joinpoint throws an exception.
	 */
	Object proceed() throws Throwable;

	/**
	 * Returns the object that holds the current joinpoint's static part.
	 * <p>
	 * For instance, the target object for an invocation.
	 * 
	 * @return the object (can be null if the accessible object is static).
	 */
	Object getThis();

	/**
	 * Returns the static part of this joinpoint.
	 * <p>
	 * The static part is an accessible object on which a chain of interceptors
	 * are installed.
	 */
	AccessibleObject getStaticPart();
}
